Drug delivery devices are commonly implanted in a patient for long-term administration of drugs. These devices generally include a chamber with a self-sealing silicone septum and a catheter attached to the chamber and positioned for delivery of the drug to a suitable location, for example, into a vein. The chamber contains the drug for delivery to the patient through the catheter and is implanted such that the septum is located just under the skin of the patient. In order to access the chamber, the patient's skin and the septum of the drug delivery device are pierced using a needle and the drug is introduced into the chamber by injection using a syringe or other delivery device.
Conventional hypodermic needles are not used for the introduction of a drug to a drug delivery device for various reasons including, for example, the possibility that these needles can damage the septum. Instead, specially designed needles are used to pierce the skin and the septum. These needles include a right angle bend (approximately a ninety degree bend) for convenient access to the chamber and are designed to inhibit coring of the septum and ensure penetration of the skin and septum at approximately ninety degrees. The needles are appropriately sized to access the chamber of the device. A portion of the needle lies approximately parallel with the surface of the skin of the patient, to allow the needle to be taped down.
While they are an improvement over conventional needles, right-angle needles can still be somewhat difficult to hold and to push through the skin and the septum since the physician must firmly grasp the needle in order to drive the needle through the septum. Also, when taped down on the patient, prior art needles do not allow flow of air around the wound site. This can contribute to infection of the wound.
One particular prior art drug delivery needle is disclosed in U.S. Pat. No. 4,743,231, issued May 10, 1988 to Kay et al. This patent teaches a right angle drug administration needle with a rigid base for taping down to the skin of a patient and a releasably connectable handle for ease of handling. A foam pad extends around the periphery of the underside of the base and includes an adhesive surface for adhering to the skin of the patient. A low profile allows for the right angled needle device to be taped down to the user while the foam pad provides flow of air around the wound site.
Although this structure provides a handle for firmly grasping the needle and a foam pad for flow of air around the wound site, the drug delivery needle device still suffers from some disadvantages. The handle is molded separately from the remainder of the needle device and is releasable to provide a low profile when the device is taped down. Thus, when the tape is removed from the patient, the physician is required to find the handle and attach the handle to the base in order to remove the needle. Since the handle is removable, it can easily be misplaced or lost. Also, the base is rigid and does not conform to the skin surface of the patient.
Accordingly, it is an object of an aspect of the present invention to provide a drug delivery needle for percutaneous delivery of a drug into an implanted drug delivery device that obviates or mitigates at least one of the disadvantages of the prior art.